Method of preparing calcium firmed frozen apple slices



Patented Nov. as, 1 950 Ms'rnon' or rnaranmo osmium Frauen FROZEN urns suoas I Claude H. Hills, Philadelphia, Pa., assignor to United States of America as represented by the Secretary of Agriculture No Drawing. Application January 30,1948,

Serlal-No. 5,480.. t

Claims; (61.99-100) JR Granted under the m, or March a, 1888, as amended April 30, 19 28; 370 0. G. 757) This application is made under the act of March' .3, 1883, as amended by the act of April 30, 1928,

and the invention herein described, if patented in any country, may be manufactured and used by or for the Government of the United States of Americ for governmental purposes throughout the world without the payment to me of any royalty thereon. jf This invention relates to treatment offruit material and more particularly to a method of improving the consistency of frozen apple slices.

Air-the present time a considerable portion of the annual apple crop cannot be utilized for commercial processing, such as canning or freezing, and is wasted or diverted to less economical uses because the fruit is too soft to withstand treatment by conventional methods. The lack of firm-- ness of the apple tissue which causes it to disintegrate on processing and handling, or to acquire an unattractive mushy appearance on subsequent cooking, may be due to overrlpe condition or may constitute an inherent characteristic of a given variety.

. dilute calcium chloride solution, or by adding calcium chloride to the sirup used to cover the frozen'shces. These procedures, however, do not An object of this invention, accordingly, is to V ing storage and on thawing is to steam-blanch the slices prior to freezing. Usually the blanched slices are then cooled by dipping in, or spraying with, cold water.

I have found that the texture and consistency of apple slices are'improved if the blanched slices arecooled by contacting them with an aqueous solution containing a calcium salt. I have found further that'when the apple tissues are very soft due to an overripe condition, a more pronounced firming effect is attained if the blanched shoes are cooled by contacting them with an aqueous solution containing a calcium salt and an alka- It is known that the consistency of plant tissues can be altered by the action of soluble calcium salts. Thus, it has been proposed to prevent disintegration of apple spices by dipping them in a' solution of calcium chloride prior to baking,

canning, or freezing. Apple slices to be frozen have also been firmed by blanching them in a" tables therein,"has"the' following on essing fresh apples forrefrigeration. i 'Th following examples are illustrative of the yield entirely satisfactory results since they cause only the surface of the shoes to be firmed without affecting the consistency of the underlying tissues, and produce apple slices, the interior of which remains soft and mushy. Such externally firmed apple shces do not handle. properly inthe subsequent freezing, thawing, and processes. In contradistinction hereto, the" process of the present invention produces a more evenly distributed effect upon the whole body of fruit tissue and yields firmed apple slices which display the same improved consistency throughout the entire shce.

According to this invention, the blanched apple slices are cooled, preferably by dipping in, or spraying with, an aqueous solution of a calcium salt, the temperature of said solution being sufflciently below that of the blanched slices to pro duce a cooling efiect on contact therewith. If a more pronounced firming effect is desired, for example, when the apple tissue treated is very soft due to overripe condition, an alkahne buil'er, such as sodium acetate, di-sodium phosphate, or sodium carbonate is added to the aqueous calcium salt solution used to cool the blanched apple slices.

The process may be conducted using a solution iof any non-toxic, water-soluble calcium salt such as calcium chloride, calcium acetate, calcium glu conate, and the hire, which may be utili'zedfat concentrations of about from 0.2 percent to 2.0

percent, the concentration of calcium salt re-' quired to attain the best results' varying withthe variety and maturity of-the apples.

Coohng of the blanched apple slices is usually effected by means of a calcium salt solution mainaqueous solution of a calcium salt in the pres.-

ence or in the absence of an alkahne bufler is a highly effective and economical method of firming apple slices and is readily adaptabl for use in combination with conventional steps of procinvention. The firmness rating," shown-in the i 3 ascsleofiltohdequslssauoeconsistenomt equals optimum firmness. and 5 equals tough.

EXAMPLE! Firm. ripe Rambo apples were peeled, cored, and sliced into twelfths. The slices were then blanched with steam at atmospheric pressure for 90 seconds, and cooled by dipp s in a solution of calcium chloride. The slices. were then drained, packaged, and placed in a freezing cabinet at -20 C. The next day the frozen slices were thawed and cooked in hollingwater for 20 minutes. n cooling the cooked slices were ex- 4 EXAMPLE Firm ripe imam apple slices were blanched with steam at atmospheric pressure for 90 seconds and cooled by dipping for minutes in soaged, and froun. The tollowins day the frozen slices were thawedycooked as described in the foregoing examples, and examined for iirmness.

A control batch of apple slices was treated exactly in the same manner except that the blanched slices were cooled by dipping for 5 minutes in distilled water.

amined for firmness. The results obtained are shown in the following a control batch of apple slices was s me table.

' mu m t at Mm 50mm magnum Iirmness 1L--- Distilled water eon rol)--. Verysnft 1 it 0.; sq. sol. oi s0 |.2Hs0------- Optimum ilrmness.-.- I 18. 0.5 sq. so]. of CaC 1.2Hs0 do 8 14.--- 1. sq. sol. of CM) :.2Ha0 do I 2. aq. sol. oi Cs0.|.2H:0.-.-. Tooiirm 4 exactly in the same. manner except that the EXAMPLE 1v blanched slices were cooled by dipping-in distllled water.

The results obtained are shown in the following A 5-pound batch of apple slices was blanched so as described in the foregoing examples and cooled by dipping for 5 minutes in 1 percent calcium table: chloride solution. The slices were then frosen Tablle 1 Duration of Firm- Coolin Solution Cooling in mummy ness No. 5 solution Cooked Apple Slices Ram Mine.

l Distilled water (control). Va ft 1 2 1% 0110112310 in water 30 0p um iirmness 3 3 do 10 r o 3 4 do 5 r n 3 5 (In n 3 It will be observed that the time of contact as at 20' C. The next day the frozen slices were with the calcium chloride solution is not critical since periods ranging from 2 to satisfactory results.

EXAMPLE II Ripe McIntosh apples were peeled, cored, and

sliced into twelfths. The slices were blanched with steam at atmospheric pressure for 90 sec- 30 minutes gave curls and cooled to room temperature by spray- Table I1 thawed and baked into pies. A control batch of apple slices was treated exactly in the same manner except that the blanched slices were cooled by dipping for '5 minutes in distilled water. The firmed slices held up very well on baking whereas the control batch disintegrated to an applesauce consistency on cooking.

EXAMPLEV with steam at atmospheric pressure for 90 seconds and cooled by dipping for 5 minutes in a solution containing 0.5 percent calcium chloride and 1.5 percent sodium acetate as an alkaline buffer. The slices were then drained, packaged, and frozen. The following day the frozen slices were thawed, cooked as described in the foregoing examples and examined for firmness.

, Two control batches of apple slices were treated E t. Cousistency oi Cooked Firmness 15 Apple Slices Rating 6 Distilled water oontrol).-.--. 0 7 0.1% no. 301. 0! hChJHsO... I 8.--- 0.21% sq. sol. oi CaCinZHsO--- l 9 0.50% sq. sol. or CsChJHrO--- Nearly optimum ilrmnel... 2 10..----- 1.0% sq. sol. of CsCls.2HsO.. do 2K lutions containing from 0.2 to 3 percent calcium chloride. The slices were then drained, pack- Firm, ripe McIntosh apple slices were blanched in the same manner except that one batch of blanched slices was dipped for 5 minutes in 0.5 percent calcium chloride solution and the second batch was dipped for 5 minutes in distilled water.

4. The process of claim 1 wherein the calcium 5 salt is calcium gluconate.

5. A processof improving the consistency of apple tissues comprising reducing fresh apples to The results are shown in the following table: 5 suitable pieces, blanching the pieces-by exposing Table IV Expt. Consistenc oiCookedA le Firmness Cooling Solution PP Ram 16"--- Distilled water control) Very soft 1 17 0.6 aq.sol.oi aCla.2Hs0-- Nearlyoptimumiirmness... 2+ 18 0.5 0 sq. sol. oi CaOlaZlLO Optimum firmness 8- plus 1.5% sodium acetate.

Although in the foregoing examples the process of my invention is described using calcium chloride as the calcium salt and sodium acetate as the alkaline buifer, similar results are obtained by analogous procedures using aqueous solutions containing eqnimolecular concentrations of other calcium salts such as calcium acetate and calcium gluconate, and alkaline buflers such as di-sodium phosphate and sodium carbonate.

When the apple tissue is so soft that the slices disintegrate on handling after blanching, the apple slices can be dipped in calcium chloride solution'prior to blanching. The slices so treated are flrmed on the surface and thus excessive mashing and disintegration during blanching is prevented. If the blanched slices are then cooled by dipping in or spraying with a solution of a calcium salt (with or without added alkaline buffer) the interior of the slices is firmed to give a slice of uniform consistency.

Having thus described my invention, I claim:

1. A process of improving the consistency of apple tissues comprising reducing fresh apples to suitable pieces, blanching the pieces by exposing them to the action of live steam, and cooling the blanched apple pieces by contacting them with an aqueous solution containing a calcium salt in a concentration of about from .2 to 2.0%.

2. The process of claim 1 wherein thcalcium salt is calcium chloride.

3. The process of claim 1 wherein the calcium salt is calcium acetate.

them to the action of live steam. and cooling the blanched apple pieces by contacting them with an aqueous solution containing a calcium salt in a. concentration of about from .2 to 2.0% and an alkaline buffer.

6. The process of claim 5 wherein the alkaline buiier is sodium acetate.

7. The process of claim 5 wherein the butter is di-sodium phosphate.

8. The process of claim 5 wherein the buffer is sodium carbonate.

9. The process of claim 5 wherein the calcium salt is calcium chloride and the alkaline buifer is'sodium acetate.

10. A process of improving the consistency of apple tissues comprising reducing fresh apples to suitable pieces, blanching the pieces by exposing them to the action oi live steam, and cooling the blanched apple pieces to about room temperature by contacting them with an aqueous solution containing a calcium salt in a concentration of about from .2 to 2.0%.

' cmopn 11.1mm.

asraaancas crrnp The following references are of record in the file of this patent:

Kertesz-The Canner-vol. 88 No. I p. 26 (loss). 

1. A PROCESS OF IMPROVING THE CONSISTENCY OF APPLE TISSUES COMPRISING REDUCING FRESH APPLES TO SUITABLE PIECES, BLANCHING THE PIECES BY EXPOSSING THEM TO THE ACTION OF LIVE STEAM, AND COOLING THE BLANCHED APPLE PIECES BY CONTACTING THEM WITH AN AQUEOUS SOLUTION CONTAINING A CALCIUM SALT IN A CONCENTRATION OF ABOUT FROM .2 TO 2.0%. 